Spider Wows Scientists With its Insect Repelling Silk

Though we might think that a spider would want as many bugs as possible in its web, being overrun by ants is actually a major threat to the eight legged hunters. However, researcher Daiqin Li from the National University of Singapore noticed that ants seemed disinterested in attacking the intricate webs of the golden orb web spiders (Nephila antipodiana). After some investigation, Li and his team determined that this was because the spider spins a powerful chemical weapon into its silk.

To conduct his research, Li partnered with the University of Melbourne to conduct a survey of the spider’s silk, figuring that it contained something that held the ants at bay. After methodically exposing ants to the myriad of chemicals present in the silk, the team eventually settled on pyrrolidine alkaloid. Though the substance itself was not a new discovery, but its insect repelling properties were a surprise.

In their work with ants and golden orb web spiders, the team also discovered that although the use of chemical deterrents may be present in other spiders, smaller spiders need not bother. It seems that although ants are impossibly tiny to us, they are simply too heavy to walk on the webs of smaller spiders. This means that if any other arachnids are lacing their silk with nasty chemicals, it’s likely to be spinners like the golden orb spider, which weave large and robust webs.

Though very powerful and effective at keeping insects away, the scientists found that pyrrolidine alkaloid was not fatal. This could, perhaps, mean that the spiders bug repellant of choice could one day have human applications. However, since the spiders don’t seem too bothered by it, any such product might have limited utility for the arachnophobic.